1. Field of the Invention
The present invention generally relates to an information supplying system using a display apparatus associated with a computer, and more specifically to a history display apparatus for displaying a history of operations by a user in a system having a hypermedia structure in which the user moves between information sources by following links provided between nodes.
2.Description of the Prior Art
In a system having a hypermedia structure, information can be browsed by following links provided between nodes. In conventional hypermedia systems, however, a problem may often occur in which a path that one has followed is lost and he cannot return to a desired location or one becomes unable to make out his whereabouts in the system. This problem is generally known as the problem of lost path in the hypermedia system.
Conventional systems often have history files that tell the routes one has followed. Generally, most of such history files simply list character information in the order in which one has been browsing. Some of the history files indicate the hypermedia links in a tree structure to allow grasping of the connection state of the links, while others show the nodes in images reduced in size.
Problem Intended to Be Solved by the Invention
However, the above-mentioned methods of displaying the history in the conventional hypermedia systems involve the following problems. First, because the history simply lists the nodes in temporal order, one cannot grasp the node to access at a glance. For example, the history of an Internet browser (viewing software) shows only URLs (Uniform Resource Locators) that indicate the titles and addresses of pages concerned. Therefore, such a simple listing hardly matches a sense of the routes a user has followed so far among information sources, thereby making it troublesome for the user to locate desired pages from among the character strings.
The conventional history display methods do not appropriately show access frequency information, so that the user cannot make distinction between nodes frequently accessed and nodes seldom accessed. Namely, the conventional methods do not take into consideration the visual representation of the access frequency information.
The conventional history display methods do not take into consideration the visual representation of user preferences, so that distinction is hardly made between frequently accessed type and/or regions and seldom accessed type and/or regions ("type" is used to mean genre or category in this specification). Namely, user preferences are not formed in a map which visually represents them.
Displaying all the accessed nodes on a map increases the numbers of nodes and links too much. And, although the user often remembers the nodes having parentage in a group, the conventional display methods show the nodes without parental distinction.
As for a conventional history display method in which history display of nodes having a hypermedia structure represents structural information, the structure itself is represented by a tree structure. Therefore, the link structure is seen as it is, making the history display too complex to grasp for users who are novice or not very familiar with computers.
The conventional methods do not provide such information other than node history as a system error in tracing past history, providing the user with no clue in the tracing.
Type classification based on existing node lists does not match the conceptual system held by the user.